Wood and wood-based substrates, such as paper, particleboard, wood composites, plastic lumbers, rope, etc., are often treated in order to impart desired characteristics to or enhance existing characteristics of the substrate. Non-limiting examples of performance characteristics which can be imparted or enhanced by treatment of a substrate with additives are durability, fire resistance and water resistance. Non-limiting examples of such appearance characteristics are color and texture. Non-limiting examples of additives which can be applied are colorants, pigments, polymers, water repellants, dimensional stabilizing agents, UV inhibitors, UV absorbers, UV blockers, antioxidants, fire retardants and biocides, such as, for example, insecticides, fungicides, moldicides, algaecides and bactericides.
Many, if not most such additives have little or no water solubility and are thus difficult to apply to wood as a water-based solution. Generally, such additives have been dissolved in organic carriers prior to use, often with the additional step of emulsification in water by the use of various surfactants if a water-based application is desired.
Solubilizing agents or surfactants such as emulsifying agents, wetting agents, etc. are added in order to give a product that can be applied as a water-based composition to wood or cellulosic substrates. However, solubilizing agents or surfactants, etc. are costly and the use of these products may also result in enhanced leaching of additive upon exposure of treated wood to moisture. It is thought that the enhanced leaching is due to the fact that solubilizing agents, surfactants, emulsifying agents, wetting agents, etc. remain in the wood after treatment. Upon exposure to moisture, the additives are solubilized or otherwise mobilized, and leach from the wood.
Despite the efforts of many inventors, there remains a need for organic preservative systems which do not require organic solubilizing agents, which are suitable for use in the treatment wood and cellulose-based materials, and have only low levels of leaching, if any, upon exposure of treated materials to the environment. This need is satisfied by the compositions disclosed herein.